Friedrich Kluge, An Etymological Dictionary of the German Language (1891)
“ In investigating a German word, we cannot and must not stop at Middle High German, the only earlier stage of our mother-tongue with which every educated man has some acquaintance; and even Old High German, the oldest literary period of German, is not, except in a very few cases, sufficient for the needs of the etymologist who knows how to appreciate the importance of philology in acquiring a knowledge of the history of the German language. ”
